Assessment of hemodynamic changes in the systemic and pulmonary arterial circulation in patients with cystic fibrosis using phase-contrast MRI

Cystic fibrosis (CF) leads to disabling lung disease and pulmonary hypertension (PH). The goal of this study was to assess the hemodynamics in the systemic and pulmonary arterial circulation of patients with CF using MRI. Ten patients with CF and 15 healthy volunteers were examined (1.5-T MRI). Phase-contrast flow measurements were assessed in the ascending aorta, pulmonary trunc, and the left and right pulmonary arteries (PA), resulting in the following parameters: peak velocity (PV) (centimeters per second) velocity rise gradient (VRG), time to PV (milliseconds), and the average area (centimeters squared). The blood flow ratio between the right and left lungs and the bronchosystemic shunt were calculated. For the ascending aorta and pulmonary trunc no parameter was significantly different between both populations. In the right PA a significantly lower PV (p=0.001) and VRG (p=0.02) was found. In the left PA there was a significantly (p=0.007) lower PV but no significant (p=0.07) difference between the VRG. The areas of the right (p=0.08) and left (p=0.5) PA were not significantly enlarged. For the volunteers a linear increase of PV in both PA was found with age, while it decreased in patients with CF. The blood flow distribution (right/left lung) showed no significant (p=0.7) difference between the groups. There was a significantly (p<0.001) higher bronchosystemic shunt volume in patients with CF (1.3 l/min) than in volunteers (0.1 l/min). Magnetic resonance based flow measurements in the right and left PA showed first indications for early development of PH. The significant increase in bronchosystemic shunt volume might be indicative fo the extent of parenchymal changes. (orig.)