[Magnetic resonance imaging of the degree of pulmonary edema using a macromolecular contrast medium].

PURPOSE: Development and experimental validation of a method tor the quantification of pulmonary oedema by measurement of total lung water and intravascular lung water and by calculation of extravascular lung water.

MATERIAL AND

METHODS

Isolated sheep lung preparations with unilateral pulmonary oedema were perfused (pulsatile pump) and examined under ventilatory arrest and during ventilation. Total lung water was calculated from proton density obtained from a multi-spin echo sequence and gravimetrically (reference method). Pulmonary intravascular volume was calculated from signal intensity histograms obtained from 3D-TOF MR-angiograms before and after application of the macromolecular contrast medium gadolinium-DTPA-polylysine. The reference method was a dye-dilution technique. Extravascular lung water was calculated as the difference between total lung water and pulmonary intravascular volume.

RESULTS

Under ventilatory arrest, the magnetic resonance technique for the measurement of extravascular lung water correlated well with the reference technique (r = 0.89, n = 42 lungs). In 10 lungs the correlation coefficients were r = 0.95 (ventilatory arrest) and r = 0.92 (ventilated lungs).

CONCLUSION

The results demonstrate that magnetic resonance imaging enhanced by a macromolecular contrast medium may be applicable for quantification of pulmonary oedema.