Can a constant bubble concentration be achieved during a long term infusion of Luminity™?

Aims: 1. To evaluate if a constant high concentration of contrast bubbles during long term infusion of 1.2mL ultrasound contrast agent (UCA) dissolved in 100mL saline over 15 and 33min can be achieved.

2. To evaluate if a constant low concentration of UCA dissolved in blood during a long term infusion over 16 and 33min can be achieved.

Methods: 1.2mL Luminity™ dissolved in a bag of 100mL saline were infused through a silicon tube with a 3mm lumen running through a tissue mimicking phantom at a visually estimated volume flow rate of approximately 1 and 2 drops/second. Every 2 minutes a short cine loop was digitally recorded and signal intensity measured on a logarithmic scale. In a second trial 0,1mL Luminity was dissolved in a 400ml blood bag in order to mimic a physiological bubble concentration in the tube. US device: LOGIQ 9 (GE Healthcare, Germany), TX: 9L, Coded Phase Inversion Mode.

Results: A constant signal enhancement over up to 33 minutes in the saline infusion was measured (1drop/s: 36.1±0.70dB; 2drops/s: 34.5±0,80dB). In the blood flow model with a contrast flow velocity of 1.5cm/s (1drop/s) and 3.2cm/s (2drops/s), a signal enhancement of 35.5dB±0.34dB and 35.9dB±0.54dB respectively could be held constant during the same period of time.

Conclusions: Using an infusion with a high or low bubble concentration dissolved in saline or human blood, enhancement levels could be held constant over up to 33 minutes. UCA infusion thus provides a long diagnostic window and a good precondition for replenishment examinations.