Contrast-enhanced three dimensional MR angiography of pulmonary artery and pulmonary perfusion imaging in pig - a comparison study with DSA

CEMRA and PPI were performed in 6 healthy pigs and 3 pulmonary embolism models with the gadolinium contrast agents inject rate 3ml/s in different doses (5ml, 10ml, 15ml, 20ml, 25ml) by comparison with DSA, in order to optimize the injection protocol and to evaluate its value in the diagnosis of experimental acute pulmonary embolism. The signal intensities and the signal to noise ratio (SNR) of the pig pulmonary arteries kept increasing with the dosage of agents, but the best angio-pulmonary contrast occurred in 10-15ml(0.25mmol/kgsimilar to0.375mmol/kg), while the satisfied dosage for PPI was 15-20ml(0.375mmol/kgsimilar to0.5mmolkg). Although CEMRA demonstrating less obstructed pulmonary arteries than DSA (8/10), but it becomes better (10/10) when combined with PPI. The pulmonary infarction zones showed wedge-shaped perfusion defects in the PPI images, which signal intensity were lower than that of normal areas (137.86+/-45.32 Vs 330.14 +/- 46.52, t = 8.40, p < 0.001). We concluded that the best dose of contrast agent for CEMRA was 0.25mmol/kgsimilar to0.375mmol/kg, and that for lung perfusion was 0.375mmol/kgsimilar to0.5mmol/kg. It is showed that CEMRA combined with PPI were better than DSA in demonstrating pulmonary embolism.