RELATIVE QUANTIFICATION OF PULMONARY-EDEMA WITH NONCONTRAST-ENHANCED MRI

Pulmonary edema is a debilitating effect of acute respiratory distress syndrome. The ability to measure it noninvasively with high sensitivi ty and in three dimensions could be useful in not only detection but a lso in assessment and guidance of treatment, To this end, a three-dime nsional MRI pulse sequence to measure the formation of edema was devel oped and tested. Another sequence was tested to measure blood now in d istal pulmonary arteries, Pulmonary edema was induced in nine dogs via venous injections of oleic acid, Edema was verified by wet-to-dry wei ght ratio (5.30 +/- .38) and extra-vascular lung water at baseline (2. 03 +/- 1.12 ml/g dry lung weight) versus postinjury (3.00 +/- 1.45 ml/ g) (P < .005). The signal-to-noise ratio within the lungs increased fr om 5.47 +/- 1.00 at baseline to 7.51 +/- 1.96 (P <.005), and the time course of edema formation was resolved. Results from MR phase-contrast blood flow measurements were variable, The authors conclude that the three-dimensional scan provides a sensitive relative quantification of pulmonary edema formation without the use of contrast agents or ioniz ing radiation.