Lung imaging using oxygen-enhanced MRI in small animals

BACKGROUND Oxygen enhanced magnetic resonance imaging (OE-MRI) is a novel method of assessing regional ventilation and oxygen diffusion from the alveoli into the capillaries of the lung. The paramagnetic nature of oxygen and deoxyhemoglobin in blood shortens the T1 of the oxygenated tissues. MRI can visualize the effect by a signal increase on T1 weighted images acquired with subjects during breathing of increased oxygen concentration compared ata on the utility of this technique in rodents are limited. to room air. D S To develop a protocol for OE-MRI on freely breathing live rodents. OBJECTIVE METHODS A T1-measurement protocol for the lung was established. Measurements on both Nickel-doped agarose gel phantoms and living rat lungs for optimization with respect to repetition time/inversion time/echo train length at a 4.7 T MRI scanner were performed. An optimized cardiac triggered inversion recovery RARE imaging sequence was developed. In order to achieve adequate signal from the lung parenchyma, maintaining practical acquisition ompensating for rapid physiological motion. times, and c RESULTS The optimized parameters from the phantom studies were: repetition time of 6000 ms, 6 inversion time values and an echo train length of 6. The mean T1 was measured with ardiac triggering to 1682 ± 203 ms (12 %) and 1769 ± 188 ms (11 %) in the right and left y. c lung, respectivel CONCLUSIONS An optimized T1-measurement protocol was established for OE-MRI in rodents. Due to hardware problems that affected the images with ghosting artifacts no conclusions can be drawn about the oxygen-induced changes.