The effects of respiratory cycle and body position on quantitative pulmonary perfusion by Magnetic Resonance Imaging

Methods Eight healthy volunteers (ages 30 to 69 years, 6 males) were prospectively enrolled. Using a saturation recovery SSFP technique, first pass perfusion images were acquired on a 1.5 T scanner. A voxel size of 4 × 2.6 × 15 mm3 was achieved in 3 parallel coronal slices in anterior, mid and posterior lung fields. After injection of gadopentetate (0.01 mmol/kg) dynamic images were acquired with a breath hold during inspiration and expiration in supine and prone positions. The contours of left and right lung parenchyma were drawn manually. The dynamic signal intensity in the pulmonary artery and in the lung parenchyma was measured over time and transferred to a proprietary model-independent deconvolution program. Absolute perfusion was then calculated using pulmonary artery dynamic contrast signal as input and that in the lung parenchyma as the distribution of tracer residence. Pulmonary perfusion was the average of the left and right lung perfusion in anterior, mid and posterior lung fields.