Diaphragmatic motion: fast gradient-recalled-echo MR imaging in healthy subjects.

Abstract

To investigate the feasibility of imaging diaphragmatic motion with a fast gradient-recalled-echo (GRE) magnetic resonance (MR) pulse sequence. Fast GRE pulse sequences in sagittal and coronal planes were used to acquire repeated, single-level, 1.2-second scans in 10 healthy volunteers during deliberately slowed, approximate-vital-capacity breathing. Motion was analyzed subjectively by viewing the image sequences as cine loops and quantitatively by measuring the displacement of different points on the diaphragm at a workstation. Temporal and spatial resolutions were adequate in all subjects. Absolute excursion of the domes was 4.4 cm on the right and 4.2 cm on the left. Analysis of diaphragmatic displacement at different locations revealed a gradient of excursion that increased from anterior to middle to posterior (P < .05-.001; paired t test). Excursion of the lateral aspects was greater than that of the medial aspect (P < .001). Fast GRE MR imaging can be reliably used to demonstrate diaphragmatic motion and may prove useful in the investigation of normal and abnormal respiratory mechanics.