Fig. 2

A, B A gadolinium-filled catheter in the left pulmonary artery of another patient. A The proposed real-time T1-weighted spoiled gradient echo image containing bright, isolated gadolinium filled balloon signal (orange arrow) with suppressed anatomical detail. B The real-time image from (A) with a manually-selected threshold applied to overlay the brightest (isolated catheter) signal on the high-resolution 3D dataset acquired at the beginning of the session. This provides the interventionalist with both high-resolution anatomical detail and clear visualization of the gadolinium- filled balloon wedge catheter tip. C, D The catheter in the Glenn anastomosis of a different patient using the bSSFP pSAT acquisition (C), and the proposed T1-overlay technique (D) demonstrating improved visualization of the catheter tip and anatomy. This improved catheter tracking can be further appreciated in Additional file 1, which shows the real-time T1-weighted images of the catheter in another patient during a right heart catheterization, and the resulting iSuite overlay that is projected into the scan room to guide the interventionalist