ROI Placement and Flow-Time-Curves. Phase contract MRI images of the CSF for a patient with scleroderma-associated PAH (mPAP 49 mmHg) during rest (top row: A, B) and adenosine-induced stress (bottom row: D, E). The red ROI is drawn around the coronary sinus, the blue ROI is placed in adjacent myocardium to correct for through-plane motion. The flow-time curves (C, F) demonstrate that net CSF increased only slightly from rest (0.86 ml/min/g) to stress (1.32 ml/min/g), resulting in a CFR of 1.53. Correspondingly, there is only little change in the diameter of and flow signal within the coronary sinus.