VeriQ C™ Intraoperative ultrasound imaging and TTFM in a single system – the new paradigm VeriQ C combines ultrasound imaging and proven transit time flow measurement (TTFM) in a single system that is specifically designed for cardiovascular procedures. Transit Time Flow Measurement (TTFM) should be used to verify graft patency, as recommended by guidelines issued jointly in 2010 by the European Society of Cardiology (ESC) and European Association for Cardio-Thoracic Surgery (EACTS).