[Sensitivity of new color systems: "maximum entropy method" and angio-color. Comparative in vitro flow measurements]. / Sensitivität neuer Farbysteme: "Maximum Entropy Method" und Angio-Farbe. Vergleichende in-vitro-Flussmessungen.

ABSTRACT

AIM: The sensitivity of the two procedures for slow blood flow velocities in two flow phantoms examined and compared to conventional colour Doppler. METHOD: In two phantoms with vessels between 0.3 and 6 mm diameter the slowest measurable blood flow with the different techniques was determined. The influence of various application angles was also studied. RESULTS: The slowest blood flow velocity detected with the MEM technique was 0.6 mm/s and with the angio-technique 0.4 mm/s. Two different scan-heads were used; a 5 MHz probe for the MEM procedures and a 10 MHz probe for ultrasound angiography. Using a 10 MHz scan-head will most likely lead to increased sensitivity of MEM. Blood flow representation with the MEM technique is real-time, while several seconds of acquisition time are required for the angio-technique, which is a disadvantage during clinical use. Conventional Doppler was merely able to represent 15 mm/s blood flow. The angio-technique was less dependent on the application angle than the MEM procedure. CONCLUSION: The definitely increased sensitivity of the two colour methods open up new areas in the diagnosis of organ and tumour perfusion.