Cardiac MRI-guided catheterization offers an alternative to conventional fluoroscopy. This technique has been used in congenital heart disease for diagnostic purposes using passive tracking methods, with either CO2 or gadolinium filled balloon wedge catheters. The gadolinium filled balloon is easier to visualize. The sequence, real-time bSSFP, can be used with or without saturation prepulse, leading to either suppression of soft tissue signal or poor catheter visualization. We have developed a partial saturation pulse sequence providing high contrast between tissue, blood and balloon. After optimization in phantoms and volunteers, this sequence has shown excellent results during MR-guided catheterization in patients.